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lib/bitmap: split-out string-related operations to a separate files

Browse Source 
lib/bitmap.c and corresponding include/linux/bitmap.h are intended to
hold functions related to operations on bitmaps, like bitmap_shift or
bitmap_set. Historically, some string-related operations like
bitmap_parse are also reside in lib/bitmap.c.

Now that the subsystem evolves, string-related bitmap operations became a
significant part of the file. Because they are quite different from the
other bitmap functions by nature, it's worth to split them to a separate
source/header files.

CC: Andrew Morton <akpm@linux-foundation.org>
CC: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
This commit is contained in:
Yury Norov 2023-10-07 16:35:10 -07:00
parent 7733aa8938
commit aae06fc1b5
6 changed files with 530 additions and 530 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
MAINTAINERS
View File

@ -3506,12 +3506,14 @@ R: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
R: Rasmus Villemoes <linux@rasmusvillemoes.dk>
S: Maintained
F: include/linux/bitfield.h
F: include/linux/bitmap-str.h
F: include/linux/bitmap.h
F: include/linux/bits.h
F: include/linux/cpumask.h
F: include/linux/find.h
F: include/linux/nodemask.h
F: include/vdso/bits.h
F: lib/bitmap-str.c
F: lib/bitmap.c
F: lib/cpumask.c
F: lib/cpumask_kunit.c

16
include/linux/bitmap-str.h Normal file
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@ -0,0 +1,16 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_BITMAP_STR_H
#define __LINUX_BITMAP_STR_H
int bitmap_parse_user(const char __user *ubuf, unsigned int ulen, unsigned long *dst, int nbits);
int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, int nmaskbits);
extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count);
extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count);
int bitmap_parse(const char *buf, unsigned int buflen, unsigned long *dst, int nbits);
int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits);
int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
unsigned long *dst, int nbits);
#endif /* __LINUX_BITMAP_STR_H */

18
include/linux/bitmap.h
View File

@ -10,6 +10,7 @@
#include <linux/limits.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/bitmap-str.h>
struct device;
@ -200,14 +201,6 @@ bitmap_find_next_zero_area(unsigned long *map,
align_mask, 0);
}
int bitmap_parse(const char *buf, unsigned int buflen,
unsigned long *dst, int nbits);
int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
unsigned long *dst, int nbits);
int bitmap_parselist(const char *buf, unsigned long *maskp,
int nmaskbits);
int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
unsigned long *dst, int nbits);
void bitmap_remap(unsigned long *dst, const unsigned long *src,
const unsigned long *old, const unsigned long *new, unsigned int nbits);
int bitmap_bitremap(int oldbit,
@ -220,15 +213,6 @@ int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
int bitmap_print_to_pagebuf(bool list, char *buf,
const unsigned long *maskp, int nmaskbits);
extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count);
extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count);
#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))

2
lib/Makefile
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@ -48,7 +48,7 @@ obj-y += bcd.o sort.o parser.o debug_locks.o random32.o \
bsearch.o find_bit.o llist.o memweight.o kfifo.o \
percpu-refcount.o rhashtable.o base64.o \
once.o refcount.o rcuref.o usercopy.o errseq.o bucket_locks.o \
generic-radix-tree.o
generic-radix-tree.o bitmap-str.o
obj-$(CONFIG_STRING_SELFTEST) += test_string.o
obj-y += string_helpers.o
obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o

510
lib/bitmap-str.c Normal file
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@ -0,0 +1,510 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/bitmap.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/hex.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include "kstrtox.h"
/**
* bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
*
* @ubuf: pointer to user buffer containing string.
* @ulen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*/
int bitmap_parse_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
char *buf;
int ret;
buf = memdup_user_nul(ubuf, ulen);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
kfree(buf);
return ret;
}
EXPORT_SYMBOL(bitmap_parse_user);
/**
* bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
* @list: indicates whether the bitmap must be list
* @buf: page aligned buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
*
* Output format is a comma-separated list of decimal numbers and
* ranges if list is specified or hex digits grouped into comma-separated
* sets of 8 digits/set. Returns the number of characters written to buf.
*
* It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
* area and that sufficient storage remains at @buf to accommodate the
* bitmap_print_to_pagebuf() output. Returns the number of characters
* actually printed to @buf, excluding terminating '\0'.
*/
int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
int nmaskbits)
{
ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
}
EXPORT_SYMBOL(bitmap_print_to_pagebuf);
/**
* bitmap_print_to_buf - convert bitmap to list or hex format ASCII string
* @list: indicates whether the bitmap must be list
* true: print in decimal list format
* false: print in hexadecimal bitmask format
* @buf: buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
* @off: in the string from which we are copying, We copy to @buf
* @count: the maximum number of bytes to print
*/
static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count)
{
const char *fmt = list ? "%*pbl\n" : "%*pb\n";
ssize_t size;
void *data;
data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);
if (!data)
return -ENOMEM;
size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);
kfree(data);
return size;
}
/**
* bitmap_print_bitmask_to_buf - convert bitmap to hex bitmask format ASCII string
* @buf: buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
* @off: in the string from which we are copying, We copy to @buf
* @count: the maximum number of bytes to print
*
* The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
* cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
* bitmask and decimal list to userspace by sysfs ABI.
* Drivers might be using a normal attribute for this kind of ABIs. A
* normal attribute typically has show entry as below::
*
* static ssize_t example_attribute_show(struct device *dev,
* struct device_attribute *attr, char *buf)
* {
* ...
* return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
* }
*
* show entry of attribute has no offset and count parameters and this
* means the file is limited to one page only.
* bitmap_print_to_pagebuf() API works terribly well for this kind of
* normal attribute with buf parameter and without offset, count::
*
* bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
* int nmaskbits)
* {
* }
*
* The problem is once we have a large bitmap, we have a chance to get a
* bitmask or list more than one page. Especially for list, it could be
* as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
* It turns out bin_attribute is a way to break this limit. bin_attribute
* has show entry as below::
*
* static ssize_t
* example_bin_attribute_show(struct file *filp, struct kobject *kobj,
* struct bin_attribute *attr, char *buf,
* loff_t offset, size_t count)
* {
* ...
* }
*
* With the new offset and count parameters, this makes sysfs ABI be able
* to support file size more than one page. For example, offset could be
* >= 4096.
* bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their
* cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf()
* make those drivers be able to support large bitmask and list after they
* move to use bin_attribute. In result, we have to pass the corresponding
* parameters such as off, count from bin_attribute show entry to this API.
*
* The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
* is similar with cpumap_print_to_pagebuf(), the difference is that
* bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
* the destination buffer is exactly one page and won't be more than one page.
* cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other
* hand, mainly serves bin_attribute which doesn't work with exact one page,
* and it can break the size limit of converted decimal list and hexadecimal
* bitmask.
*
* WARNING!
*
* This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
* It is intended to workaround sysfs limitations discussed above and should be
* used carefully in general case for the following reasons:
*
* - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
* - Memory complexity is O(nbits), comparing to O(1) for snprintf().
* - @off and @count are NOT offset and number of bits to print.
* - If printing part of bitmap as list, the resulting string is not a correct
* list representation of bitmap. Particularly, some bits within or out of
* related interval may be erroneously set or unset. The format of the string
* may be broken, so bitmap_parselist-like parser may fail parsing it.
* - If printing the whole bitmap as list by parts, user must ensure the order
* of calls of the function such that the offset is incremented linearly.
* - If printing the whole bitmap as list by parts, user must keep bitmap
* unchanged between the very first and very last call. Otherwise concatenated
* result may be incorrect, and format may be broken.
*
* Returns the number of characters actually printed to @buf
*/
int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count)
{
return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
}
EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
/**
* bitmap_print_list_to_buf - convert bitmap to decimal list format ASCII string
* @buf: buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
* @off: in the string from which we are copying, We copy to @buf
* @count: the maximum number of bytes to print
*
* Everything is same with the above bitmap_print_bitmask_to_buf() except
* the print format.
*/
int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count)
{
return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
}
EXPORT_SYMBOL(bitmap_print_list_to_buf);
/*
* Region 9-38:4/10 describes the following bitmap structure:
* 0 9 12 18 38 N
* .........****......****......****..................
* ^ ^ ^ ^ ^
* start off group_len end nbits
*/
struct region {
unsigned int start;
unsigned int off;
unsigned int group_len;
unsigned int end;
unsigned int nbits;
};
static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
{
unsigned int start;
for (start = r->start; start <= r->end; start += r->group_len)
bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
}
static int bitmap_check_region(const struct region *r)
{
if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
return -EINVAL;
if (r->end >= r->nbits)
return -ERANGE;
return 0;
}
static const char *bitmap_getnum(const char *str, unsigned int *num,
unsigned int lastbit)
{
unsigned long long n;
unsigned int len;
if (str[0] == 'N') {
*num = lastbit;
return str + 1;
}
len = _parse_integer(str, 10, &n);
if (!len)
return ERR_PTR(-EINVAL);
if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
return ERR_PTR(-EOVERFLOW);
*num = n;
return str + len;
}
static inline bool end_of_str(char c)
{
return c == '\0' || c == '\n';
}
static inline bool __end_of_region(char c)
{
return isspace(c) || c == ',';
}
static inline bool end_of_region(char c)
{
return __end_of_region(c) || end_of_str(c);
}
/*
* The format allows commas and whitespaces at the beginning
* of the region.
*/
static const char *bitmap_find_region(const char *str)
{
while (__end_of_region(*str))
str++;
return end_of_str(*str) ? NULL : str;
}
static const char *bitmap_find_region_reverse(const char *start, const char *end)
{
while (start <= end && __end_of_region(*end))
end--;
return end;
}
static const char *bitmap_parse_region(const char *str, struct region *r)
{
unsigned int lastbit = r->nbits - 1;
if (!strncasecmp(str, "all", 3)) {
r->start = 0;
r->end = lastbit;
str += 3;
goto check_pattern;
}
str = bitmap_getnum(str, &r->start, lastbit);
if (IS_ERR(str))
return str;
if (end_of_region(*str))
goto no_end;
if (*str != '-')
return ERR_PTR(-EINVAL);
str = bitmap_getnum(str + 1, &r->end, lastbit);
if (IS_ERR(str))
return str;
check_pattern:
if (end_of_region(*str))
goto no_pattern;
if (*str != ':')
return ERR_PTR(-EINVAL);
str = bitmap_getnum(str + 1, &r->off, lastbit);
if (IS_ERR(str))
return str;
if (*str != '/')
return ERR_PTR(-EINVAL);
return bitmap_getnum(str + 1, &r->group_len, lastbit);
no_end:
r->end = r->start;
no_pattern:
r->off = r->end + 1;
r->group_len = r->end + 1;
return end_of_str(*str) ? NULL : str;
}
/**
* bitmap_parselist - convert list format ASCII string to bitmap
* @buf: read user string from this buffer; must be terminated
* with a \0 or \n.
* @maskp: write resulting mask here
* @nmaskbits: number of bits in mask to be written
*
* Input format is a comma-separated list of decimal numbers and
* ranges. Consecutively set bits are shown as two hyphen-separated
* decimal numbers, the smallest and largest bit numbers set in
* the range.
* Optionally each range can be postfixed to denote that only parts of it
* should be set. The range will divided to groups of specific size.
* From each group will be used only defined amount of bits.
* Syntax: range:used_size/group_size
* Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
* The value 'N' can be used as a dynamically substituted token for the
* maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
* dynamic, so if system changes cause the bitmap width to change, such
* as more cores in a CPU list, then any ranges using N will also change.
*
* Returns: 0 on success, -errno on invalid input strings. Error values:
*
* - ``-EINVAL``: wrong region format
* - ``-EINVAL``: invalid character in string
* - ``-ERANGE``: bit number specified too large for mask
* - ``-EOVERFLOW``: integer overflow in the input parameters
*/
int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
{
struct region r;
long ret;
r.nbits = nmaskbits;
bitmap_zero(maskp, r.nbits);
while (buf) {
buf = bitmap_find_region(buf);
if (buf == NULL)
return 0;
buf = bitmap_parse_region(buf, &r);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = bitmap_check_region(&r);
if (ret)
return ret;
bitmap_set_region(&r, maskp);
}
return 0;
}
EXPORT_SYMBOL(bitmap_parselist);
/**
* bitmap_parselist_user() - convert user buffer's list format ASCII
* string to bitmap
*
* @ubuf: pointer to user buffer containing string.
* @ulen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
* Wrapper for bitmap_parselist(), providing it with user buffer.
*/
int bitmap_parselist_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
char *buf;
int ret;
buf = memdup_user_nul(ubuf, ulen);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = bitmap_parselist(buf, maskp, nmaskbits);
kfree(buf);
return ret;
}
EXPORT_SYMBOL(bitmap_parselist_user);
static const char *bitmap_get_x32_reverse(const char *start,
const char *end, u32 *num)
{
u32 ret = 0;
int c, i;
for (i = 0; i < 32; i += 4) {
c = hex_to_bin(*end--);
if (c < 0)
return ERR_PTR(-EINVAL);
ret |= c << i;
if (start > end || __end_of_region(*end))
goto out;
}
if (hex_to_bin(*end--) >= 0)
return ERR_PTR(-EOVERFLOW);
out:
*num = ret;
return end;
}
/**
* bitmap_parse - convert an ASCII hex string into a bitmap.
* @start: pointer to buffer containing string.
* @buflen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0 or \n. In that case,
* UINT_MAX may be provided instead of string length.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
* Commas group hex digits into chunks. Each chunk defines exactly 32
* bits of the resultant bitmask. No chunk may specify a value larger
* than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
* then leading 0-bits are prepended. %-EINVAL is returned for illegal
* characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
* Leading, embedded and trailing whitespace accepted.
*/
int bitmap_parse(const char *start, unsigned int buflen,
unsigned long *maskp, int nmaskbits)
{
const char *end = strnchrnul(start, buflen, '\n') - 1;
int chunks = BITS_TO_U32(nmaskbits);
u32 *bitmap = (u32 *)maskp;
int unset_bit;
int chunk;
for (chunk = 0; ; chunk++) {
end = bitmap_find_region_reverse(start, end);
if (start > end)
break;
if (!chunks--)
return -EOVERFLOW;
#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
#else
end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
#endif
if (IS_ERR(end))
return PTR_ERR(end);
}
unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
if (unset_bit < nmaskbits) {
bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
return 0;
}
if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
return -EOVERFLOW;
return 0;
}
EXPORT_SYMBOL(bitmap_parse);

512
lib/bitmap.c
View File

@ -6,21 +6,11 @@
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/thread_info.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include "kstrtox.h"
/**
* DOC: bitmap introduction
@ -440,508 +430,6 @@ unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
}
EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
/*
* Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
* second version by Paul Jackson, third by Joe Korty.
*/
/**
* bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
*
* @ubuf: pointer to user buffer containing string.
* @ulen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*/
int bitmap_parse_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
char *buf;
int ret;
buf = memdup_user_nul(ubuf, ulen);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
kfree(buf);
return ret;
}
EXPORT_SYMBOL(bitmap_parse_user);
/**
* bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
* @list: indicates whether the bitmap must be list
* @buf: page aligned buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
*
* Output format is a comma-separated list of decimal numbers and
* ranges if list is specified or hex digits grouped into comma-separated
* sets of 8 digits/set. Returns the number of characters written to buf.
*
* It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
* area and that sufficient storage remains at @buf to accommodate the
* bitmap_print_to_pagebuf() output. Returns the number of characters
* actually printed to @buf, excluding terminating '\0'.
*/
int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
int nmaskbits)
{
ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
}
EXPORT_SYMBOL(bitmap_print_to_pagebuf);
/**
* bitmap_print_to_buf - convert bitmap to list or hex format ASCII string
* @list: indicates whether the bitmap must be list
* true: print in decimal list format
* false: print in hexadecimal bitmask format
* @buf: buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
* @off: in the string from which we are copying, We copy to @buf
* @count: the maximum number of bytes to print
*/
static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count)
{
const char *fmt = list ? "%*pbl\n" : "%*pb\n";
ssize_t size;
void *data;
data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);
if (!data)
return -ENOMEM;
size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);
kfree(data);
return size;
}
/**
* bitmap_print_bitmask_to_buf - convert bitmap to hex bitmask format ASCII string
* @buf: buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
* @off: in the string from which we are copying, We copy to @buf
* @count: the maximum number of bytes to print
*
* The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
* cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
* bitmask and decimal list to userspace by sysfs ABI.
* Drivers might be using a normal attribute for this kind of ABIs. A
* normal attribute typically has show entry as below::
*
* static ssize_t example_attribute_show(struct device *dev,
* struct device_attribute *attr, char *buf)
* {
* ...
* return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
* }
*
* show entry of attribute has no offset and count parameters and this
* means the file is limited to one page only.
* bitmap_print_to_pagebuf() API works terribly well for this kind of
* normal attribute with buf parameter and without offset, count::
*
* bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
* int nmaskbits)
* {
* }
*
* The problem is once we have a large bitmap, we have a chance to get a
* bitmask or list more than one page. Especially for list, it could be
* as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
* It turns out bin_attribute is a way to break this limit. bin_attribute
* has show entry as below::
*
* static ssize_t
* example_bin_attribute_show(struct file *filp, struct kobject *kobj,
* struct bin_attribute *attr, char *buf,
* loff_t offset, size_t count)
* {
* ...
* }
*
* With the new offset and count parameters, this makes sysfs ABI be able
* to support file size more than one page. For example, offset could be
* >= 4096.
* bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their
* cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf()
* make those drivers be able to support large bitmask and list after they
* move to use bin_attribute. In result, we have to pass the corresponding
* parameters such as off, count from bin_attribute show entry to this API.
*
* The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
* is similar with cpumap_print_to_pagebuf(), the difference is that
* bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
* the destination buffer is exactly one page and won't be more than one page.
* cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other
* hand, mainly serves bin_attribute which doesn't work with exact one page,
* and it can break the size limit of converted decimal list and hexadecimal
* bitmask.
*
* WARNING!
*
* This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
* It is intended to workaround sysfs limitations discussed above and should be
* used carefully in general case for the following reasons:
*
* - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
* - Memory complexity is O(nbits), comparing to O(1) for snprintf().
* - @off and @count are NOT offset and number of bits to print.
* - If printing part of bitmap as list, the resulting string is not a correct
* list representation of bitmap. Particularly, some bits within or out of
* related interval may be erroneously set or unset. The format of the string
* may be broken, so bitmap_parselist-like parser may fail parsing it.
* - If printing the whole bitmap as list by parts, user must ensure the order
* of calls of the function such that the offset is incremented linearly.
* - If printing the whole bitmap as list by parts, user must keep bitmap
* unchanged between the very first and very last call. Otherwise concatenated
* result may be incorrect, and format may be broken.
*
* Returns the number of characters actually printed to @buf
*/
int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count)
{
return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
}
EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
/**
* bitmap_print_list_to_buf - convert bitmap to decimal list format ASCII string
* @buf: buffer into which string is placed
* @maskp: pointer to bitmap to convert
* @nmaskbits: size of bitmap, in bits
* @off: in the string from which we are copying, We copy to @buf
* @count: the maximum number of bytes to print
*
* Everything is same with the above bitmap_print_bitmask_to_buf() except
* the print format.
*/
int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
int nmaskbits, loff_t off, size_t count)
{
return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
}
EXPORT_SYMBOL(bitmap_print_list_to_buf);
/*
* Region 9-38:4/10 describes the following bitmap structure:
* 0 9 12 18 38 N
* .........****......****......****..................
* ^ ^ ^ ^ ^
* start off group_len end nbits
*/
struct region {
unsigned int start;
unsigned int off;
unsigned int group_len;
unsigned int end;
unsigned int nbits;
};
static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
{
unsigned int start;
for (start = r->start; start <= r->end; start += r->group_len)
bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
}
static int bitmap_check_region(const struct region *r)
{
if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
return -EINVAL;
if (r->end >= r->nbits)
return -ERANGE;
return 0;
}
static const char *bitmap_getnum(const char *str, unsigned int *num,
unsigned int lastbit)
{
unsigned long long n;
unsigned int len;
if (str[0] == 'N') {
*num = lastbit;
return str + 1;
}
len = _parse_integer(str, 10, &n);
if (!len)
return ERR_PTR(-EINVAL);
if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
return ERR_PTR(-EOVERFLOW);
*num = n;
return str + len;
}
static inline bool end_of_str(char c)
{
return c == '\0' || c == '\n';
}
static inline bool __end_of_region(char c)
{
return isspace(c) || c == ',';
}
static inline bool end_of_region(char c)
{
return __end_of_region(c) || end_of_str(c);
}
/*
* The format allows commas and whitespaces at the beginning
* of the region.
*/
static const char *bitmap_find_region(const char *str)
{
while (__end_of_region(*str))
str++;
return end_of_str(*str) ? NULL : str;
}
static const char *bitmap_find_region_reverse(const char *start, const char *end)
{
while (start <= end && __end_of_region(*end))
end--;
return end;
}
static const char *bitmap_parse_region(const char *str, struct region *r)
{
unsigned int lastbit = r->nbits - 1;
if (!strncasecmp(str, "all", 3)) {
r->start = 0;
r->end = lastbit;
str += 3;
goto check_pattern;
}
str = bitmap_getnum(str, &r->start, lastbit);
if (IS_ERR(str))
return str;
if (end_of_region(*str))
goto no_end;
if (*str != '-')
return ERR_PTR(-EINVAL);
str = bitmap_getnum(str + 1, &r->end, lastbit);
if (IS_ERR(str))
return str;
check_pattern:
if (end_of_region(*str))
goto no_pattern;
if (*str != ':')
return ERR_PTR(-EINVAL);
str = bitmap_getnum(str + 1, &r->off, lastbit);
if (IS_ERR(str))
return str;
if (*str != '/')
return ERR_PTR(-EINVAL);
return bitmap_getnum(str + 1, &r->group_len, lastbit);
no_end:
r->end = r->start;
no_pattern:
r->off = r->end + 1;
r->group_len = r->end + 1;
return end_of_str(*str) ? NULL : str;
}
/**
* bitmap_parselist - convert list format ASCII string to bitmap
* @buf: read user string from this buffer; must be terminated
* with a \0 or \n.
* @maskp: write resulting mask here
* @nmaskbits: number of bits in mask to be written
*
* Input format is a comma-separated list of decimal numbers and
* ranges. Consecutively set bits are shown as two hyphen-separated
* decimal numbers, the smallest and largest bit numbers set in
* the range.
* Optionally each range can be postfixed to denote that only parts of it
* should be set. The range will divided to groups of specific size.
* From each group will be used only defined amount of bits.
* Syntax: range:used_size/group_size
* Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
* The value 'N' can be used as a dynamically substituted token for the
* maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
* dynamic, so if system changes cause the bitmap width to change, such
* as more cores in a CPU list, then any ranges using N will also change.
*
* Returns: 0 on success, -errno on invalid input strings. Error values:
*
* - ``-EINVAL``: wrong region format
* - ``-EINVAL``: invalid character in string
* - ``-ERANGE``: bit number specified too large for mask
* - ``-EOVERFLOW``: integer overflow in the input parameters
*/
int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
{
struct region r;
long ret;
r.nbits = nmaskbits;
bitmap_zero(maskp, r.nbits);
while (buf) {
buf = bitmap_find_region(buf);
if (buf == NULL)
return 0;
buf = bitmap_parse_region(buf, &r);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = bitmap_check_region(&r);
if (ret)
return ret;
bitmap_set_region(&r, maskp);
}
return 0;
}
EXPORT_SYMBOL(bitmap_parselist);
/**
* bitmap_parselist_user() - convert user buffer's list format ASCII
* string to bitmap
*
* @ubuf: pointer to user buffer containing string.
* @ulen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
* Wrapper for bitmap_parselist(), providing it with user buffer.
*/
int bitmap_parselist_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
char *buf;
int ret;
buf = memdup_user_nul(ubuf, ulen);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = bitmap_parselist(buf, maskp, nmaskbits);
kfree(buf);
return ret;
}
EXPORT_SYMBOL(bitmap_parselist_user);
static const char *bitmap_get_x32_reverse(const char *start,
const char *end, u32 *num)
{
u32 ret = 0;
int c, i;
for (i = 0; i < 32; i += 4) {
c = hex_to_bin(*end--);
if (c < 0)
return ERR_PTR(-EINVAL);
ret |= c << i;
if (start > end || __end_of_region(*end))
goto out;
}
if (hex_to_bin(*end--) >= 0)
return ERR_PTR(-EOVERFLOW);
out:
*num = ret;
return end;
}
/**
* bitmap_parse - convert an ASCII hex string into a bitmap.
* @start: pointer to buffer containing string.
* @buflen: buffer size in bytes. If string is smaller than this
* then it must be terminated with a \0 or \n. In that case,
* UINT_MAX may be provided instead of string length.
* @maskp: pointer to bitmap array that will contain result.
* @nmaskbits: size of bitmap, in bits.
*
* Commas group hex digits into chunks. Each chunk defines exactly 32
* bits of the resultant bitmask. No chunk may specify a value larger
* than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
* then leading 0-bits are prepended. %-EINVAL is returned for illegal
* characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
* Leading, embedded and trailing whitespace accepted.
*/
int bitmap_parse(const char *start, unsigned int buflen,
unsigned long *maskp, int nmaskbits)
{
const char *end = strnchrnul(start, buflen, '\n') - 1;
int chunks = BITS_TO_U32(nmaskbits);
u32 *bitmap = (u32 *)maskp;
int unset_bit;
int chunk;
for (chunk = 0; ; chunk++) {
end = bitmap_find_region_reverse(start, end);
if (start > end)
break;
if (!chunks--)
return -EOVERFLOW;
#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
#else
end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
#endif
if (IS_ERR(end))
return PTR_ERR(end);
}
unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
if (unset_bit < nmaskbits) {
bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
return 0;
}
if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
return -EOVERFLOW;
return 0;
}
EXPORT_SYMBOL(bitmap_parse);
/**
* bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
* @buf: pointer to a bitmap